add io.md in doc
add io.md in doc

tlby/mxnet,arikpoz/mxnet,jamesliu/mxnet,apaleyes/mxnet,madjam/mxnet,ptrendx/mxnet,kkk669/mxnet,larroy/mxnet,Prasad9/incubator-mxnet,dmlc/mxnet,jamesliu/mxnet,tlby/mxnet,navrasio/mxnet,leezu/mxnet,hotpxl/mxnet,EvanzzzZ/mxnet,precedenceguo/mxnet,xcgoner/dist-mxnet,Ldpe2G/mxnet,Ldpe2G/mxnet,arank/mxnet,dmlc/mxnet,hpi-xnor/BMXNet,tlby/mxnet,crazy-cat/incubator-mxnet,ShownX/incubator-mxnet,rishita/mxnet,nicklhy/mxnet,arank/mxnet,LinkHS/incubator-mxnet,lxn2/mxnet,danithaca/mxnet,solin319/incubator-mxnet,wangyum/mxnet,kevinthesun/mxnet,piiswrong/mxnet,DR08/mxnet,ykim362/mxnet,DickJC123/mxnet,likelyzhao/mxnet,zhreshold/mxnet,TuSimple/mxnet,wangyum/mxnet,coder-james/mxnet,mbaijal/incubator-mxnet,arikpoz/mxnet,yuruofeifei/mxnet,piiswrong/mxnet,jermainewang/mxnet,jiajiechen/mxnet,smolix/incubator-mxnet,likelyzhao/mxnet,weleen/mxnet,danithaca/mxnet,solin319/incubator-mxnet,kevinthesun/mxnet,vikingMei/mxnet,larroy/mxnet,TuSimple/mxnet,TuSimple/mxnet,rahul003/mxnet,xcgoner/dist-mxnet,likelyzhao/mxnet,lxn2/mxnet,saurabh3949/mxnet,xcgoner/dist-mxnet,rahul003/mxnet,Prasad9/incubator-mxnet,fullfanta/mxnet,szha/mxnet,sergeykolychev/mxnet,tornadomeet/mxnet,Ldpe2G/mxnet,apaleyes/mxnet,stefanhenneking/mxnet,ZihengJiang/mxnet,yajiedesign/mxnet,reminisce/mxnet,hpi-xnor/BMXNet,saurabh3949/mxnet,Guneet-Dhillon/mxnet,jennyzhang0215/incubator-mxnet,kevinthesun/mxnet,precedenceguo/mxnet,leezu/mxnet,smolix/incubator-mxnet,jermainewang/mxnet,rishita/mxnet,EvanzzzZ/mxnet,lxn2/mxnet,hotpxl/mxnet,thirdwing/mxnet,CodingCat/mxnet,danithaca/mxnet,sxjscience/mxnet,szha/mxnet,szha/mxnet,yajiedesign/mxnet,jennyzhang0215/incubator-mxnet,antoan2/incubator-mxnet,fullfanta/mxnet,navrasio/mxnet,madjam/mxnet,lxn2/mxnet,rahul003/mxnet,danithaca/mxnet,apache/incubator-mxnet,ForkedReposBak/mxnet,lxn2/mxnet,eric-haibin-lin/mxnet,ZihengJiang/mxnet,solin319/incubator-mxnet,TuSimple/mxnet,Mega-DatA-Lab/mxnet,formath/mxnet,jennyzhang0215/incubator-mxnet,sergeykolychev/mxnet,piiswrong/mxnet,coder-james/mxnet,antoan2/incubator-mxnet,leezu/mxnet,piiswrong/mxnet,kkk669/mxnet,arikpoz/mxnet,CodingCat/mxnet,eric-haibin-lin/mxnet,Northrend/mxnet,jiajiechen/mxnet,jiajiechen/mxnet,jennyzhang0215/incubator-mxnet,arikpoz/mxnet,TuSimple/mxnet,jamesliu/mxnet,dmlc/mxnet,kevinthesun/mxnet,larroy/mxnet,ykim362/mxnet,apache/incubator-mxnet,kevinthesun/mxnet,ForkedReposBak/mxnet,Guneet-Dhillon/mxnet,jermainewang/mxnet,vikingMei/mxnet,Northrend/mxnet,tornadomeet/mxnet,DR08/mxnet,jiajiechen/mxnet,larroy/mxnet,larroy/mxnet,pluskid/mxnet,reminisce/mxnet,ForkedReposBak/mxnet,likelyzhao/mxnet,arank/mxnet,weleen/mxnet,saurabh3949/mxnet,szha/mxnet,smolix/incubator-mxnet,nicklhy/mxnet,arikpoz/mxnet,kevinthesun/mxnet,leezu/mxnet,sergeykolychev/mxnet,Ldpe2G/mxnet,EvanzzzZ/mxnet,kkk669/mxnet,EvanzzzZ/mxnet,apaleyes/mxnet,solin319/incubator-mxnet,Prasad9/incubator-mxnet,likelyzhao/mxnet,formath/mxnet,indhub/mxnet,eric-haibin-lin/mxnet,eric-haibin-lin/mxnet,xcgoner/dist-mxnet,ShownX/incubator-mxnet,yuruofeifei/mxnet,jamesliu/mxnet,ykim362/mxnet,fullfanta/mxnet,hotpxl/mxnet,DR08/mxnet,sergeykolychev/mxnet,leezu/mxnet,mbaijal/incubator-mxnet,LinkHS/incubator-mxnet,crazy-cat/incubator-mxnet,tornadomeet/mxnet,reminisce/mxnet,hesseltuinhof/mxnet,antoan2/incubator-mxnet,solin319/incubator-mxnet,ForkedReposBak/mxnet,TuSimple/mxnet,fullfanta/mxnet,tlby/mxnet,hesseltuinhof/mxnet,ptrendx/mxnet,apaleyes/mxnet,yajiedesign/mxnet,mbaijal/incubator-mxnet,Mega-DatA-Lab/mxnet,Northrend/mxnet,Ldpe2G/mxnet,saurabh3949/mxnet,leezu/mxnet,reminisce/mxnet,zhreshold/mxnet,stefanhenneking/mxnet,luoyetx/mxnet,precedenceguo/mxnet,szha/mxnet,DR08/mxnet,jennyzhang0215/incubator-mxnet,jiajiechen/mxnet,antoan2/incubator-mxnet,weleen/mxnet,ptrendx/mxnet,pluskid/mxnet,sxjscience/mxnet,sxjscience/mxnet,Northrend/mxnet,hotpxl/mxnet,arank/mxnet,tlby/mxnet,danithaca/mxnet,gautamkmr/incubator-mxnet,Mega-DatA-Lab/mxnet,coder-james/mxnet,dmlc/mxnet,antoan2/incubator-mxnet,xcgoner/dist-mxnet,LinkHS/incubator-mxnet,tlby/mxnet,rishita/mxnet,DR08/mxnet,jermainewang/mxnet,Mega-DatA-Lab/mxnet,ZihengJiang/mxnet,Ldpe2G/mxnet,sergeykolychev/mxnet,arikpoz/mxnet,Northrend/mxnet,DickJC123/mxnet,indhub/mxnet,kevinthesun/mxnet,pluskid/mxnet,yuruofeifei/mxnet,likelyzhao/mxnet,nicklhy/mxnet,indhub/mxnet,arank/mxnet,thirdwing/mxnet,ykim362/mxnet,saurabh3949/mxnet,piiswrong/mxnet,ShownX/incubator-mxnet,EvanzzzZ/mxnet,LinkHS/incubator-mxnet,yuruofeifei/mxnet,jiajiechen/mxnet,sxjscience/mxnet,madjam/mxnet,sxjscience/mxnet,rahul003/mxnet,indhub/mxnet,crazy-cat/incubator-mxnet,hesseltuinhof/mxnet,navrasio/mxnet,reminisce/mxnet,saurabh3949/mxnet,crazy-cat/incubator-mxnet,tlby/mxnet,szha/mxnet,DR08/mxnet,kevinthesun/mxnet,reminisce/mxnet,solin319/incubator-mxnet,luoyetx/mxnet,yuruofeifei/mxnet,jermainewang/mxnet,zhreshold/mxnet,LinkHS/incubator-mxnet,nicklhy/mxnet,Guneet-Dhillon/mxnet,coder-james/mxnet,dmlc/mxnet,ZihengJiang/mxnet,jermainewang/mxnet,ShownX/incubator-mxnet,wangyum/mxnet,szha/mxnet,formath/mxnet,sxjscience/mxnet,stefanhenneking/mxnet,luoyetx/mxnet,ptrendx/mxnet,smolix/incubator-mxnet,CodingCat/mxnet,piiswrong/mxnet,mbaijal/incubator-mxnet,Northrend/mxnet,wangyum/mxnet,vikingMei/mxnet,luoyetx/mxnet,indhub/mxnet,eric-haibin-lin/mxnet,madjam/mxnet,rahul003/mxnet,reminisce/mxnet,larroy/mxnet,kkk669/mxnet,ForkedReposBak/mxnet,gautamkmr/incubator-mxnet,hpi-xnor/BMXNet,jermainewang/mxnet,tornadomeet/mxnet,sergeykolychev/mxnet,hotpxl/mxnet,formath/mxnet,Prasad9/incubator-mxnet,gautamkmr/incubator-mxnet,Mega-DatA-Lab/mxnet,stefanhenneking/mxnet,solin319/incubator-mxnet,rahul003/mxnet,tornadomeet/mxnet,apaleyes/mxnet,likelyzhao/mxnet,antoan2/incubator-mxnet,xcgoner/dist-mxnet,hotpxl/mxnet,CodingCat/mxnet,CodingCat/mxnet,LinkHS/incubator-mxnet,ykim362/mxnet,yajiedesign/mxnet,stefanhenneking/mxnet,coder-james/mxnet,eric-haibin-lin/mxnet,DR08/mxnet,pluskid/mxnet,hpi-xnor/BMXNet,stefanhenneking/mxnet,jiajiechen/mxnet,piiswrong/mxnet,jennyzhang0215/incubator-mxnet,lxn2/mxnet,apaleyes/mxnet,mbaijal/incubator-mxnet,rishita/mxnet,ptrendx/mxnet,fullfanta/mxnet,vikingMei/mxnet,larroy/mxnet,stefanhenneking/mxnet,coder-james/mxnet,hpi-xnor/BMXNet,gautamkmr/incubator-mxnet,TuSimple/mxnet,CodingCat/mxnet,CodingCat/mxnet,vikingMei/mxnet,hpi-xnor/BMXNet,weleen/mxnet,navrasio/mxnet,Mega-DatA-Lab/mxnet,smolix/incubator-mxnet,Prasad9/incubator-mxnet,ykim362/mxnet,jennyzhang0215/incubator-mxnet,leezu/mxnet,hpi-xnor/BMXNet,weleen/mxnet,yuruofeifei/mxnet,jamesliu/mxnet,TuSimple/mxnet,EvanzzzZ/mxnet,larroy/mxnet,antoan2/incubator-mxnet,ForkedReposBak/mxnet,eric-haibin-lin/mxnet,wangyum/mxnet,danithaca/mxnet,ZihengJiang/mxnet,ptrendx/mxnet,arikpoz/mxnet,ykim362/mxnet,xcgoner/dist-mxnet,weleen/mxnet,coder-james/mxnet,thirdwing/mxnet,madjam/mxnet,indhub/mxnet,crazy-cat/incubator-mxnet,DickJC123/mxnet,szha/mxnet,weleen/mxnet,Ldpe2G/mxnet,tlby/mxnet,hotpxl/mxnet,apaleyes/mxnet,TuSimple/mxnet,fullfanta/mxnet,reminisce/mxnet,antoan2/incubator-mxnet,sxjscience/mxnet,pluskid/mxnet,rahul003/mxnet,eric-haibin-lin/mxnet,EvanzzzZ/mxnet,pluskid/mxnet,smolix/incubator-mxnet,ZihengJiang/mxnet,ForkedReposBak/mxnet,navrasio/mxnet,mbaijal/incubator-mxnet,yuruofeifei/mxnet,jiajiechen/mxnet,LinkHS/incubator-mxnet,hesseltuinhof/mxnet,hesseltuinhof/mxnet,ptrendx/mxnet,lxn2/mxnet,rahul003/mxnet,fullfanta/mxnet,Northrend/mxnet,zhreshold/mxnet,ykim362/mxnet,rishita/mxnet,ZihengJiang/mxnet,navrasio/mxnet,kkk669/mxnet,ShownX/incubator-mxnet,nicklhy/mxnet,sxjscience/mxnet,vikingMei/mxnet,danithaca/mxnet,gautamkmr/incubator-mxnet,gautamkmr/incubator-mxnet,sergeykolychev/mxnet,yajiedesign/mxnet,mbaijal/incubator-mxnet,navrasio/mxnet,reminisce/mxnet,fullfanta/mxnet,leezu/mxnet,dmlc/mxnet,pluskid/mxnet,Prasad9/incubator-mxnet,dmlc/mxnet,jennyzhang0215/incubator-mxnet,Prasad9/incubator-mxnet,ptrendx/mxnet,apache/incubator-mxnet,yajiedesign/mxnet,sergeykolychev/mxnet,piiswrong/mxnet,wangyum/mxnet,tornadomeet/mxnet,hesseltuinhof/mxnet,ZihengJiang/mxnet,wangyum/mxnet,smolix/incubator-mxnet,dmlc/mxnet,likelyzhao/mxnet,rishita/mxnet,tlby/mxnet,precedenceguo/mxnet,kevinthesun/mxnet,saurabh3949/mxnet,lxn2/mxnet,jamesliu/mxnet,apaleyes/mxnet,Mega-DatA-Lab/mxnet,Ldpe2G/mxnet,hotpxl/mxnet,Guneet-Dhillon/mxnet,stefanhenneking/mxnet,ForkedReposBak/mxnet,apache/incubator-mxnet,sxjscience/mxnet,CodingCat/mxnet,zhreshold/mxnet,sergeykolychev/mxnet,formath/mxnet,jermainewang/mxnet,yuruofeifei/mxnet,Guneet-Dhillon/mxnet,thirdwing/mxnet,crazy-cat/incubator-mxnet,kkk669/mxnet,yajiedesign/mxnet,hesseltuinhof/mxnet,madjam/mxnet,Prasad9/incubator-mxnet,larroy/mxnet,nicklhy/mxnet,crazy-cat/incubator-mxnet,vikingMei/mxnet,Guneet-Dhillon/mxnet,zhreshold/mxnet,hotpxl/mxnet,saurabh3949/mxnet,saurabh3949/mxnet,smolix/incubator-mxnet,weleen/mxnet,precedenceguo/mxnet,precedenceguo/mxnet,kkk669/mxnet,jamesliu/mxnet,fullfanta/mxnet,ShownX/incubator-mxnet,stefanhenneking/mxnet,xcgoner/dist-mxnet,DR08/mxnet,wangyum/mxnet,arikpoz/mxnet,hesseltuinhof/mxnet,tornadomeet/mxnet,ShownX/incubator-mxnet,yajiedesign/mxnet,leezu/mxnet,ForkedReposBak/mxnet,crazy-cat/incubator-mxnet,thirdwing/mxnet,ykim362/mxnet,luoyetx/mxnet,mbaijal/incubator-mxnet,tornadomeet/mxnet,indhub/mxnet,antoan2/incubator-mxnet,rishita/mxnet,luoyetx/mxnet,dmlc/mxnet,tlby/mxnet,zhreshold/mxnet,arank/mxnet,Guneet-Dhillon/mxnet,arank/mxnet,thirdwing/mxnet,precedenceguo/mxnet,indhub/mxnet,jiajiechen/mxnet,arank/mxnet,madjam/mxnet,LinkHS/incubator-mxnet,ZihengJiang/mxnet,precedenceguo/mxnet,TuSimple/mxnet,wangyum/mxnet,jamesliu/mxnet,vikingMei/mxnet,DR08/mxnet,EvanzzzZ/mxnet,rishita/mxnet,formath/mxnet,EvanzzzZ/mxnet,pluskid/mxnet,LinkHS/incubator-mxnet,yuruofeifei/mxnet,solin319/incubator-mxnet,nicklhy/mxnet,ShownX/incubator-mxnet,hesseltuinhof/mxnet,arank/mxnet,eric-haibin-lin/mxnet,DickJC123/mxnet,precedenceguo/mxnet,coder-james/mxnet,rishita/mxnet,danithaca/mxnet,rahul003/mxnet,zhreshold/mxnet,piiswrong/mxnet,danithaca/mxnet,pluskid/mxnet,nicklhy/mxnet,kkk669/mxnet,likelyzhao/mxnet,smolix/incubator-mxnet,solin319/incubator-mxnet,Mega-DatA-Lab/mxnet,coder-james/mxnet,apaleyes/mxnet,jermainewang/mxnet,zhreshold/mxnet,jennyzhang0215/incubator-mxnet,reminisce/mxnet,Ldpe2G/mxnet,Prasad9/incubator-mxnet,thirdwing/mxnet,ptrendx/mxnet,luoyetx/mxnet,arikpoz/mxnet,madjam/mxnet,formath/mxnet,hpi-xnor/BMXNet,Northrend/mxnet,formath/mxnet,indhub/mxnet,crazy-cat/incubator-mxnet,ptrendx/mxnet,hpi-xnor/BMXNet,xcgoner/dist-mxnet,navrasio/mxnet,Guneet-Dhillon/mxnet,gautamkmr/incubator-mxnet,madjam/mxnet,tornadomeet/mxnet,CodingCat/mxnet,yajiedesign/mxnet,Guneet-Dhillon/mxnet,Northrend/mxnet,nicklhy/mxnet,lxn2/mxnet,formath/mxnet,gautamkmr/incubator-mxnet,navrasio/mxnet,szha/mxnet,luoyetx/mxnet,vikingMei/mxnet,thirdwing/mxnet,ShownX/incubator-mxnet,thirdwing/mxnet,weleen/mxnet,luoyetx/mxnet,Mega-DatA-Lab/mxnet,gautamkmr/incubator-mxnet,jamesliu/mxnet,mbaijal/incubator-mxnet,kkk669/mxnet